1. Field of the Invention
The invention relates to a lens and a reset method thereof, in particular relates to a lens with a single detection member shared to perform focusing and zooming operations and a reset method thereof.
2. Description of the Related Art
In the past, a lens generally includes a focusing unit and a zooming unit. The focusing unit includes a focusing group frame and a focusing driving member utilized to drive the focusing group frame to move between a long-shot end and a close-shot end. The zooming unit includes a zooming group frame and a zooming driving member utilized to drive the zooming group frame to move between a wide-angle end and a telephoto end. Formally, each of the focusing unit and the zooming unit is individually provided with a detection member which is utilized to detect zero return positions of the focusing group frame and the zooming group frame. For example, Taiwan Patent Nos. I310848 and I305603 respectively disclose detection members which are respectively corresponding to the focusing unit and the zooming unit, in which the detection principle of the zooming unit relates to a cam cylinder provided with a reflecting plate, and the detection members disposed on a fixed cylinder are utilized to detect whether the position of the reflecting plate is correct or not.
However, the total cost of the lense unit is majorly decided by the amount of the detection members. If a single detection member can be shared to perform focusing and zooming operations, the total cost of the lense unit can be reduced. Therefore, one of the goals for the related manufacturers is to study and develop a lens and a reset method for the single detection member capable of controlling the positions of the focusing group frame and the zooming group frame and reducing the manufacturing cost.